This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.

The pthread_attr_getstack() and pthread_attr_setstack() functions,
respectively, shall get and set the thread creation stack attributes
stackaddr and stacksize in the attr object.
The stack attributes specify the area of storage to be used for the
created thread's stack. The base (lowest addressable byte) of the
storage shall be stackaddr, and the size of the storage shall be
stacksize bytes. The stacksize shall be at least {PTHREAD_STACK_MIN}.
The pthread_attr_setstack() function may fail with [EINVAL] if
stackaddr does not meet implementation-defined alignment
requirements. All pages within the stack described by stackaddr and
stacksize shall be both readable and writable by the thread.
If the pthread_attr_getstack() function is called before the
stackaddr attribute has been set, the behavior is unspecified.
The behavior is undefined if the value specified by the attr argument
to pthread_attr_getstack() or pthread_attr_setstack() does not refer
to an initialized thread attributes object.

Upon successful completion, these functions shall return a value of
0; otherwise, an error number shall be returned to indicate the
error.
The pthread_attr_getstack() function shall store the stack attribute
values in stackaddr and stacksize if successful.

The pthread_attr_setstack() function shall fail if:
EINVAL The value of stacksize is less than {PTHREAD_STACK_MIN} or
exceeds an implementation-defined limit.
The pthread_attr_setstack() function may fail if:
EINVAL The value of stackaddr does not have proper alignment to be
used as a stack, or ((char *)stackaddr + stacksize) lacks
proper alignment.
EACCES The stack page(s) described by stackaddr and stacksize are not
both readable and writable by the thread.
These functions shall not return an error code of [EINTR].
The following sections are informative.

These functions are appropriate for use by applications in an
environment where the stack for a thread must be placed in some
particular region of memory.
While it might seem that an application could detect stack overflow
by providing a protected page outside the specified stack region,
this cannot be done portably. Implementations are free to place the
thread's initial stack pointer anywhere within the specified region
to accommodate the machine's stack pointer behavior and allocation
requirements. Furthermore, on some architectures, such as the IA‐64,
``overflow'' might mean that two separate stack pointers allocated
within the region will overlap somewhere in the middle of the region.
After a successful call to pthread_attr_setstack(), the storage area
specified by the stackaddr parameter is under the control of the
implementation, as described in Section 2.9.8, Use of Application-Managed Thread Stacks.
The specification of the stackaddr attribute presents several
ambiguities that make portable use of these functions impossible. For
example, the standard allows implementations to impose arbitrary
alignment requirements on stackaddr. Applications cannot assume that
a buffer obtained from malloc() is suitably aligned. Note that
although the stacksize value passed to pthread_attr_setstack() must
satisfy alignment requirements, the same is not true for
pthread_attr_setstacksize() where the implementation must increase
the specified size if necessary to achieve the proper alignment.

If an implementation detects that the value specified by the attr
argument to pthread_attr_getstack() or pthread_attr_setstack() does
not refer to an initialized thread attributes object, it is
recommended that the function should fail and report an [EINVAL]
error.

Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 PTHREAD_ATTR_GETSTACK(3P)